|VW Golf Ignition Misfire
The Volkswagen 1.8L turbo engine (AGU) is used in many VW and Audi models from 1996 - 2003 including Golf, Bora, A3 and A4.This engine is known for ignition misfires. The ignition system uses 4 coils (coil on plug) and an ignition module that is triggered by the ECU.
One of the most common failures with this type of ignition system is the module fails to trigger the ignition coils. This condition is usually misdiagnosed as a faulty ignition coil.
The following information will assist to locate and rectify this problem.
- Loss of power
- Poor fuel consumption
- Codes P0301, P0302, P0303, P0304
- Engine stalling
- Locate the weak cylinder by cylinder balance test
- Check the spark output at the ignition coil. The spark should be a bright blue colour and audible.
- Another quick test is to swap the ignition coil with another coil from a different cylinder. Recheck by performing a cylinder balance test.
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Wiring Harness Tests
- Test the ignition coil power supply and earth using a multimeter [Ignition On, Battery voltage to coil]
- Test the ignition negative trigger using an LED test light [Check for primary ignition pulse]
- Check the wiring harness for open circuits as this is a common problem. Test continuity between the ignition coil and the ignition module.
Ignition Module Tests
- The ignition module is location on the air box
- Check the ignition module input and output (pulse)
- Check the earth circuit to the ignition module
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- Replace the ignition coil as required
- Replace the ignition module as required
- Repair wiring harness as required
- Check the spark plugs and replace if required